A general object lens drive unit included in the optical pickup of the optical disk unit is composed of a lens holder with an object lens loaded, a plurality of coils attached to the lens holder, a suspension wire for operatively supporting movable units including the aforementioned, a yoke, and a magnet.
When a drive current is applied to the coils, the movable units are driven by electromagnetic force generated due to an action with magnetic flux from the magnet. The drive direction includes a direction in which the object lens approaches or parts from the optical disk face, that is, a focusing. direction (z direction) which is an optic axis direction of the object lens, a tracking direction (y direction) that is perpendicular to the focusing direction and is a radial direction of the optical disk, and a tilt direction rotating round an axis in a direction (x direction) perpendicular to the focusing direction and tracking direction, and a coil corresponding to each direction is installed. Further, the driving in the tilt direction may not be realized.
The power supply to the coils is realized via the suspension wire. When the three drive directions are used, three suspension wires are accordingly arranged at both ends of the lens holder.
When assembling such an object lens drive unit, it is necessary to mechanically connect the suspension wires to the lens holder and electrically connect the suspension wires and the terminal wires of the coils.
A conventional example in which exclusive substrates for this connection are arranged at both ends of the lens holder is disclosed in Japanese Patent Laid-open No. 2007-188596 (Patent Document 1). The Patent Document 1 describes the substrates that enable decreasing the size of the substrates in the z direction so as to achieve a thin optical pickup while ensuring the operability at the time of soldering of the suspension wires.